Rv1073 Family assigned · low

H37Rv Rv1073 · MTBC0 mtbc0_001153 · 283 aa · 1205500–1206351 MTBC0 (+) · RefSeq NP_215589.1

Genomic neighbourhood (genome browser)

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Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)hypothetical protein
MTBC0 PGAP re-annotationhypothetical protein
Revised (this work)Nicking-endonuclease-like fold (type-II nicking enzyme V.NaeI-like). RefSeq leaves it 'hypothetical protein'.
Functional category (TubercuList)conserved hypotheticals

In the literature (TB corpus sweep) 1 publication

Found under: H37Rv (1).

1 TB publication mentions this gene. 1 publication(s) mention this gene (title/abstract), verified against the text. The atlas states the function; these are the primary sources that discuss it.

PublicationDate
Identification and serological characterization of MtbAg1073, a conserved Mycobacterium tuberculosis complex antigen recognized in active tuberculosis. doi:10.1265/ehpm.26-00071 2026

This layer CITES the literature, it does not change the verdict or the function. A gene may be heavily studied (as an antigen, a resistance determinant, a drug target) while its molecular function is settled elsewhere in the fiche. This distinguishes a gene that is dark because nobody has looked from one that is dark despite having been studied. Source: PubMed (whole), MULTI-ALIAS sweep: H37Rv locus tag AND every ortholog identifier (M. bovis Mb…, M. marinum MMAR_…, M. smegmatis MSMEG_…, M. leprae ML…, M. abscessus MAB_…), each hit VERIFIED against the abstract text (word-boundary regex). phase73/phase75, 2026-07-13.

Conditional expression context (iModulons)

Member of 1 independently-modulated gene set(s): Rv1776c+WhiB4 (Rv1776c and whiB4 ).

iModulon membership (independently-modulated gene sets from a 647-sample RNA-seq compendium): the conditional co-expression context. Co-expression is a regulatory context, NOT a molecular function. Source: iModulonDB / modulome_mtb (Yoo 2022).

CRISPRi vulnerability

Vulnerability index 0.77 (95% CI -1.24 to 3.84). A more negative index = more vulnerable to knockdown (better drug-target quality); indicative threshold VI ≤ -6 = highly vulnerable.

Quantitative CRISPRi knockdown, graded (finer than binary Tn-seq essentiality). Source: CRISPRi vulnerability index (Bosch 2021, pebble.rockefeller.edu).

Legacy record & comparison (Mycobrowser)

Mycobrowser functionFunction unknown

The legacy Mycobrowser record is shown for verification. Mycobrowser is no longer maintained; its EC numbers predate recent nomenclature revisions, so a class change usually reflects re-numbering, not a conflict.

Orthologues (reciprocal best hits across mycobacteria)

M. bovis Mb1102 · 100.0% identity
M. marinum MMAR_0712 · 55.3% identity
M. orygis RJtmp_001133 · 100.0% identity

Reciprocal-best-hit orthologues (DIAMOND) against the Mycobrowser reference proteomes. A missing species is informative: e.g. a gene absent from M. leprae was likely lost in its reductive genome evolution. Locus tags link to Mycobrowser.

Curated reference (UniProt)

UniProt O53421 TrEMBL · unreviewed · Predicted
UniProt nameCullin, a subunit of E3 ubiquitin ligase

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category S Function unknown
eggNOG descriptionProtein conserved in bacteria
Orthologous groupCOG2852

Orthology-based transfer (eggNOG 5.0.2, diamond). EC/KO/GO/CAZy are computed annotations, not manual curation; cross-check against the primary literature before treating a specific reaction as established.

Conservation & selection (intra-MTBC, 145 209 strains)

pN/pS 0.658 · relaxed/neutral
Polymorphic sites (≥ 0.1% of strains) 1 synonymous, 2 missense, 0 nonsense, 1 frameshift
Disruption 1 distinct premature-stop/frameshift site(s); most common in 0.21% of strains (307) · clonal

pN/pS from segregating SNPs (singletons removed) normalised by possible sites. Low pN/pS = purifying selection (a strong signal that a "hypothetical" is a real, constrained gene). A high pN/pS is ambiguous: relaxed constraint or positive selection (drug resistance, antigenic variation) inflate it; e.g. rpoB/katG/pncA score high here for resistance, not loss of function. A clonal disruption (one allele over a clade) suggests lineage pseudogenisation; a convergent one (many independent alleles) is typical of resistance loss-of-function.

Outgroup conservation (beyond the MTBC) Corynebacteriales

M. canettii dN/dS (deep-divergence selection) 0.33 (low power) · 2 consensus substitution(s)
low power (2 canettii-consensus substitution(s)); present in M. canettii but dN/dS not reliable
Genus-wide presence (~53 non-MTBC Mycobacterium) present in 52/53 (98%) · mean identity 56.9% · 4/4 closest MTBAP relatives
conserved across the genus (present in 52/53 non-MTBC Mycobacterium genomes, incl. distant relatives) — an ancient core gene predating the genus radiation
Phylostratum (deepest detected homolog) MTBC-specific Mycobacterium Mycobacteriaceae Corynebacteriales Actinomycetia Bacteria
detected in 4/13 non-Mycobacterium reference genomes (down to Corynebacteriales) · mean identity 37.3%
detected across the order Corynebacteriales (Corynebacterium/Nocardia/Rhodococcus/…) but not in more distant Actinomycetia — a Corynebacteriales-level gene

Two orthogonal outgroup signals. M. canettii (the immediate outgroup) gives a deep-divergence dN/dS (a low value confirms a constrained, real gene; shown as confident only at ≥8 substitutions, else flagged low-power). Genus-wide presence/absence (tblastn vs assembled non-MTBC genomes) places the gene on the ancient-core ↔ MTBC-specific axis: a gene absent even from the closest MTBAP relatives is a candidate MTBC-specific innovation (possible host-adaptation factor, to confirm by synteny). The phylostratum extends that axis outside the genus (tblastn vs 13 reference genomes spanning Mycobacteriaceae → Corynebacteriales → Actinomycetia → outside the phylum): it is the deepest clade in which a homolog is still detected, i.e. a proxy for gene age. Read it with the null model in mind: a shallow (young) stratum can also reflect homology-detection failure for short or fast-evolving ORFs, so it is a descriptive axis, not a proof of novelty.

Essentiality (transposon mutagenesis)

DeJesus 2017 callGA · growth-advantage
What the call meansgrowth-advantage: insertions enriched
TA sites (Himar1) 19 in the ORF — 0 in the essential state, 0 growth-defect, 5 non-essential, 14 growth-advantage. Saturation 0.947, mean read count 255.555555556. A region of the protein devoid of TA sites is invisible to this assay: nothing can be inferred about it, in either direction.

Genome-wide Himar1 transposon essentiality in H37Rv (DeJesus 2017). An essential call (ES/ESD/GD) is strong, independent evidence that a "hypothetical" locus encodes a functional, selectively required gene — orthogonal to intra-species conservation.

Proteomics (mass spectrometry) not detected

Not detected in the mass-spectrometry datasets integrated by PaxDb. This is not evidence of absence: low-abundance, condition-specific, or MS-refractory proteins (e.g. small, highly hydrophobic, or repetitive PE/PPE families with few tryptic peptides) are systematically under-sampled.

Physico-chemical properties (computed, ProtParam)

Length283 aa
Molecular weight32.0 kDa
Theoretical pI9.73
GRAVY-0.337 (hydrophilic)
Aliphatic index96.9
Aromaticity0.078
Instability index32.9 (stable)

Computed from the ancestral MTBC0 sequence with the ExPASy ProtParam method (Biopython). Descriptive biophysical context: a positive GRAVY flags a hydrophobic (often membrane) protein, a high instability index (>40) predicts a short in-vitro half-life, an extreme pI hints at compartment or binding partner.

Domains (Pfam, hmmscan --cut_ga)

No Pfam-A domain above the gathering threshold (or not yet scanned).

Structural neighbours (Foldseek on the ESMFold model, exploratory)

ESMFold model confidence: mean pLDDT 96.3 (very high). A confident model makes the fold comparison meaningful.

Best matches against the PDB, ranked by Foldseek homology probability. A high probability / TM-score suggests a shared fold; unless flagged sig (E < 0.01) these are fold hypotheses, not assignments.

TargetProbTME-valueDescription
3r3p-assembly1_B 1.00 0.72 8.3e-02 3r3p-assembly1_B Homing Endonuclease I-Bth0305I Catalytic Domain
9g6k-assembly1_L9 0.66 0.37 8.8e-02 9g6k-assembly1_L9 LSU structure derived from the LSU sample of the mitoribosome from T. gondii.
6z1p-assembly1_AS 0.35 0.32 1.3e-01 6z1p-assembly1_AS Structure of the mitochondrial ribosome from Tetrahymena thermophila
8bao-assembly1_B 0.33 0.48 1.1e+00 8bao-assembly1_B Dysgonamonadaceae bacterium CRISPR ancillary nuclease 2
2inb-assembly1_A-2 0.20 0.44 9.5e-01 2inb-assembly1_A-2 Crystal structure of an XisH family protein (ZP_00107633.1) from Nostoc punctiforme PCC 73102 at 1.60 A resolution
8b6h-assembly1_EJ 0.18 0.40 8.4e-01 8b6h-assembly1_EJ Cryo-EM structure of cytochrome c oxidase dimer (complex IV) from respiratory supercomplex of Tetrahymena thermophila
7yzm-assembly1_B 0.16 0.60 3.7e+00 7yzm-assembly1_B MgADPNP-bound DCCP:DCCP-R complex
7c2f-assembly2_D 0.15 0.49 3.1e+00 7c2f-assembly2_D Crystal Structure of the Thorarchaeota ProGel/rabbit actin complex

Genomic context (neighbours & predicted operon)

Upstream (5' on genome)Rv1072 (+ strand, 115 bp gap)
Downstream (3' on genome)fadA3 (- strand, 73 bp gap)

Neighbours from the H37Rv annotation (+ strand). The operon is predicted by co-directional intergenic distance (same strand, gaps ≤50 bp) — a transcription-unit hypothesis, not a mapped TSS. For a "hypothetical", co-transcription with a characterised operon is a concrete functional lead (complements the STRING neighborhood channel below).

Functional interaction network (STRING v12, guilt-by-association)

Explore full network →

Node colour = verdict, dashed = hypothetical; edge colour = evidence (green experimental, orange genomic-context, grey co-expression), width ∝ score. Click a partner to open its page; "Explore full network" to walk the graph.

Closest characterised functional partner: Rv1072 (transmembrane protein), medium confidence from genomic context alone (score 596 excluding text-mining). This association is the citable seed of a function hypothesis for this hypothetical protein.

PartnerProductScoreNo text-miningChannels (≥400)
Rv2744c 35kd_ag hyp hypothetical protein 687 687 coexpression:687
Rv2100 hyp hypothetical protein 651 651 ctx cooccurence:647
Rv3776 hyp hypothetical protein 648 648 ctx cooccurence:644
Rv1072 transmembrane protein 596 596 ctx neighborhood:578
Rv0393 hyp hypothetical protein 537 537 ctx cooccurence:535
Rv3859c gltB glutamate synthase large subunit 526 527 coexpression:520
Rv0767c HTH-type transcriptional regulator 526 526 ctx cooccurence:524
Rv0336 hyp hypothetical protein 493 493 ctx cooccurence:483
Rv0515 hyp hypothetical protein 493 493 ctx cooccurence:484
Rv3810 pirG cell surface protein 492 492 ctx cooccurence:489
Rv2345 transmembrane protein 460 461 ctx cooccurence:459
Rv3707c hyp hypothetical protein 437 438 ctx cooccurence:436
Rv0320 hyp hypothetical protein 433 433 ctx cooccurence:433
Rv3668c protease 429 429 ctx cooccurence:420
Rv0169 mce1A Mce family protein Mce1A 420 420

STRING combines evidence channels (neighborhood, fusion, cooccurrence, coexpression, experimental, database, text-mining) into a 0–1000 score. The ctx badge marks edges carried by the genomic-context channels (conserved neighborhood, fusion, phylogenetic co-occurrence), which are independent of orthology and structure and the strongest signal for an unknown gene. The exp badge marks an experimentally-supported partner (measured interaction, experimental/database channel ≥400) as opposed to a purely predicted one — but note that the M. tuberculosis experimental interactome is dominated by a noisy bacterial-two-hybrid screen, so a strong measured link that contradicts the operon/localisation context is likely a false positive. The no text-mining column recomputes the score from data alone, so a link that does not depend on the literature is visible. Association is a function hypothesis, not proof: corroborate with the operon context and the primary literature before assigning a function.

Evidence

  • Foldseek vs AFDB-SwissProt: type II nicking enzyme V.NaeI, TM 0.55, E 1e-3
  • Structural homology vs AlphaFold-Swiss-Prot (Foldseek; 542k curated SwissProt structures), project 'Still unknown gene function' phase13, 2026-06-10. Fold/family-level, not a demonstrated function.

Sources

  • Ancestral sequence & coordinates: Harrison LB et al. (2024), An imputed ancestral reference genome for the MTBC, doi:10.1101/2023.09.07.556366
  • Product annotation: NCBI PGAP on MTBC0; legacy from H37Rv NC_000962.3 (RefSeq NP_215589.1)
  • Domains: Pfam-A via hmmscan --cut_ga — none above threshold
  • Sequence-level signal: ESM Atlas (EvolutionaryScale × BioHub) — exploratory
  • Controlled vocabulary: eggNOG-mapper 2.1.12 (Cantalapiedra et al. 2021, doi:10.1093/molbev/msab293), eggNOG 5.0 DB (Huerta-Cepas et al. 2019) — OG COG2852
  • Curated reference: UniProt O53421 (TrEMBL, unreviewed; Predicted)
  • Intra-MTBC selection: pN/pS and disruption from SPDI variants of 145 209 MTBC strains (this work, local collection vs H37Rv NC_000962.3)
  • Model confidence: ESMFold per-residue pLDDT (mean 96.3, very high)
  • Genome-wide structure: AlphaFold DB model (Jumper et al. 2021, doi:10.1038/s41586-021-03819-2; Varadi et al. 2024, doi:10.1093/nar/gkad1011) searched vs PDB with Foldseek (mean pLDDT 93.2)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 20 functional partner(s); context anchor Rv1072
  • Essentiality: genome-wide transposon mutagenesis in H37Rv — DeJesus et al. 2017 (mBio, doi:10.1128/mBio.02133-16, CC BY)
  • Functional category: TubercuList scheme (Cole et al. 1998, doi:10.1038/31159), via Mycobrowser (Kapopoulou et al. 2011, doi:10.1016/j.tube.2010.09.006)
  • Orthologues: reciprocal best hits (DIAMOND, Buchfink et al. 2021, doi:10.1038/s41592-021-01101-x) against Mycobrowser release 5 reference proteomes
  • Genomic context / operon: H37Rv annotation; operon predicted by co-directional intergenic distance (Salgado et al. 2000, doi:10.1073/pnas.030539397)
  • Physico-chemical properties: ExPASy ProtParam method via Biopython (Gasteiger et al. 2005), computed from the MTBC0 sequence
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_001153|Rv1073|
MGAQPFIGSEALAAGLISWHELGKYYTAIMPNVYLDKRLKPSLRQRVIAAWLWSGRKGVIAGASASALHGAKWVDDHALVELIWRNARAPNGVRTKDELLLDGEVQRLCGLTVTTVERTAFDLGRRPPLGQAITRLDALANATDFKINDVRELARKHPHTRGLRQLDKALDLVDPGAQSPKETWLRLLLINAGFPRPSTQIPLLGVYGHPKYFLDMGWEDIMLAVEYDGEQHRLSRDQFVKDVERLEYIRRAGWTHIRVLADHKGPDVVRRVRQAWDTLTSRR